x25 bfe-decision

This command is no longer supported.

x25 bfe-emergency

This command is no longer supported.

x25 default

To set a default protocol that Cisco IOS software will assume applies to incoming calls with unknown or missing protocol identifier in the call user data (CUD), use the x25 default interface configuration command. To remove the default protocol specified, use the no form of this command.

x25 default protocol

no x25 default protocol

Syntax Description

protocol

Specifies the protocol to assume; may be ip or pad.

Defaults

No default protocol is specified.

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command specifies the protocol assumed by the Cisco IOS software for incoming calls with unknown or missing protocol identifier in the call user data (CUD). If you do not use the x25 default interface configuration command, the software clears any incoming calls with unrecognized CUD.

Examples

The following example establishes IP as the default protocol for X.25 calls:

interface serial 0

x25 default ip

Related Commands

x25 facility

To force facilities on a per-call basis for calls originated by the router (switched calls are not affected), use the x25 facility interface configuration command. To disable a facility, use the no form of this command.

x25 facility option value

no x25 facility option value

Syntax Description

option

Set of user facilities options. See Table 55 for a list of supported facilities and their values.

value

Option value. See Table 55 for a list of supported facilities and their values.

Defaults

No facility is sent.

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

Specifies a closed user group (CUG) number; CUGs numbered from 1 to 9999 are allowed. CUGs can be used by a public data network (PDN) to create a virtual private network within the larger network and to restrict access.

Proposes the packet count for input windows (in-size) and output windows (out-size) for flow control parameter negotiation. Both values must be in the range 1 to 127 and must not be greater than or equal to the value set for the x25 modulo command.

reverse

Specifies reverses charging on all calls originated by the interface.

throughput in out

Sets the requested throughput class negotiation values for input (in) and output (out) throughput across the network. Values for in and out are in bits per second (bps) and range from 75 to 48000 bps.

transit-delayvalue

Specifies a network transit delay to request for the duration of outgoing calls for networks that support transit delay. The transit delay value can be between 0 and 65534 milliseconds.

roaname

Specifies the name defined by the x25 roa command for a list of transit Recognized Operation Agencies (ROAs) to use in outgoing Call Request packets.

Examples

The following example specifies a transit delay value in an X.25 configuration:

interface serial 0

x25 facility transit-delay 24000

The following example sets an ROA name and then sends the list via the X.25 user facilities:

x25 roa green_list 23 35 36

interface serial 0

x25 facility roa green_list

Related Commands

x25 fail-over

To configure a secondary interface and set the number of seconds for which a primary interface must be up before the secondary interface resets, use the x25 fail-over command in the appropriate configuration mode. To prevent the secondary interface from resetting, use the no form of this command.

x25 fail-over seconds interface type number [dlci | mac-address]

no x25 fail-over seconds interface type number [dlci | mac-address]

Syntax Description

seconds

Number of seconds for which the primary interface must be up before the secondary interface resets.

interface

Secondary interface.

type

Interface type.

number

Interface number.

dlci

(Optional) DLCI number.

mac-address

(Optional) MAC address.

Defaults

No default behavior or values.

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

Release 12.1(1)T

This command was introduced.

Usage Guidelines

The x25 fail-over command can be configured on a primary X.25 interface or an X.25 profile only.

Examples

In the following example, X.25 failover is configured on a network that is also configured for Annex G. If data-link connection identifier (DLCI) 13 or DLCI 14 on serial interface 1/0 goes down, dialer interface 1 will serve as the secondary interface. After DLCI 13 or 14 comes back up and remains up for 20 seconds, dialer interface 1 will reset, sending all calls back to the primary interface.

Related Commands

Configures an X.25 profile without specifying any hardware-specific information.

x25 hic

To set the highest incoming-only virtual circuit (VC) number, use the x25 hic interface configuration command.

x25 hic circuit-number

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no incoming-only VC range.

Defaults

0

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command is applicable only if you have the X.25 switch configured for an incoming-only VC range. Incoming is from the perspective of the X.25 data terminal equipment (DTE). If you do not want any outgoing calls from your DTE, configure both ends to disable the two-way range (set the values of x25 ltc and x25 htc to 0) and configure an incoming-only range. Any incoming-only range must come before (that is, must be numerically less than) any two-way range. Any two-way range must come before any outgoing-only range.

Examples

Related Commands

x25 hoc

To set the highest outgoing-only virtual circuit (VC) number, use the x25 hoc interface configuration command.

x25 hoc circuit-number

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no incoming-only VC range.

Defaults

0

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command is applicable only if you have the X.25 switch configured for an outgoing-only VC range. Outgoing is from the perspective of the X.25 data terminal equipment (DTE). If you do not want any incoming calls on your DTE, disable the two-way range (set the values of x25 ltc and x25 htc to 0) and configure an outgoing-only range. Any outgoing-only range must come after (that is, be numerically greater than) any other range.

Examples

The following example sets a valid outgoing-only VC range of 2000 to 2005:

interface serial 0

x25 loc 2000

x25 hoc 2005

Related Commands

x25 hold-queue

To set the maximum number of packets to hold until a virtual circuit (VC) is able to send, use the x25 hold-queue interface configuration command. To remove this command from the configuration file and restore the default value, use the no form of this command without an argument.

x25 hold-queue packets

no x25 hold-queue [packets]

Syntax Description

packets

Number of packets. A hold queue value of 0 allows an unlimited number of packets in the hold queue.

Defaults

10 packets

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

If you set the queue-size argument to 0 when using the no x25 hold-queue command, there will be no hold queue limit. While this setting will prevent drops until the router runs out of memory, it is only rarely appropriate. A VC hold queue value is determined when it is created; changing this parameter will not affect the hold queue limits of the existing virtual circuits.

Related Commands

Sets the interface default maximum output packet size to match that of the network.

x25 hold-vc-timer

To start the timer that prevents additional calls to a destination for a given period of time (thus preventing overruns on some X.25 switches caused by Call Request packets), use the x25 hold-vc-timer interface configuration command. To restore the default value for the timer, use the no form of this command.

x25 hold-vc-timer minutes

no x25 hold-vc-timer

Syntax Description

minutes

Number of minutes that calls to a previously failed destination will be prevented. Incoming calls are still accepted.

Defaults

0 minutes

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

Only Call Requests that the router originates are held down; routed X.25 Call Requests are not affected by this parameter.

Upon receiving a Clear Request for an outstanding Call Request, the X.25 support code immediately tries another Call Request if it has more traffic to send, and this action might cause overrun problems.

Examples

The following example sets this timer to 3 minutes:

interface serial 0

x25 hold-vc-timer 3

x25 host

To define a static host name-to-address mapping, use the x25 host global configuration command. To remove the host name, use the no form of thecommand.

Defaults

Command Modes

Command History

Usage Guidelines

This command permits you to map an X.121 address to an easily recognizable name. You can later use this host name instead of the X.121 address when you issue the translate command for X.25.

Examples

The following example specifies a static address mapping:

x25 host Willard 4085551212

The following example removes a static address mapping:

no x25 host Willard

The following example specifies static address mapping from the X.121 address 12345678 to the host name "ocean". It then uses the name "ocean" in the translate command in place of the X.121 address when translating from the X.25 host to the PPP host with address 10.0.0.2.

x25 host ocean 12345678

translate x25 ocean ppp 10.0.0.2 routing

Related Commands

Command

Description

translate x25

When an X.25 connection request to a particular destination address is received, the Cisco router can automatically translate the request to another outgoing protocol connection type.

x25 htc

To set the highest two-way virtual circuit (VC) number, use the x25 htc interface configuration command.

x25 htc circuit-number

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no two-way VC range.

Defaults

1024 for X.25 network service interfaces; 4095 for CMNS network service interfaces.

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command is applicable if the X.25 switch is configured for a two-way VC range. Any two-way VC range must come after (that is, be numerically larger than) any incoming-only range, and must come before any outgoing-only range.

Related Commands

x25 hunt-group

To create and maintain a hunt group, use the x25 hunt-group global configuration command. To delete this hunt group, use the no form of this command.

x25 hunt-groupname{rotary | vc-count}

no x25 hunt-groupname

Syntax Description

name

Name you assign to the particular hunt group.

rotary

Each call steps to the next interface.

vc-count

Each call is placed on the interface with most available logical channels.

Command Modes

Global configuration

Command History

Release

Modification

12.0(3)T

This command was introduced.

Usage Guidelines

Only one load-balancing distribution method can be selected for a hunt group, although one interface can participate in one or more hunt groups.

The rotary distribution method sends every call to the next available interface regardless of line speed and the number of available VCs on that interface.

The vc-count distribution method sends calls to the interface with the largest number of available logical channels. This method ensures a good load balance when you have lines of equal speed. If the line speeds are unequal, the vc-count method will favor the line with the higher speed. In cases where interfaces have the same line speed, the call is sent to the interface that is defined earliest in the hunt group.

To distribute calls equally among interfaces regardless of line speed, configure each interface with the same number of VCs.

With the vc-count distribution method, if a hunt group does not contain an operational interface, the call will be forwared to the next route if one was specified. If a session is terminated on an interface within the hunt group, that interface now has more available VCs and it will be chosen next.

Examples

X.25 Load Balancing Using VC-Count Distribution Method Example

In the following example, the vc-count distribution method is used on a hunt group that contains two serial interfaces that have different numbers of VCs. Assuming no sessions are being terminated at this time, the first 450 calls will be sent to Serial1, and subsequent calls will alternate between Serial0 and Serial1 until the interfaces are full.

interface serial0

description 56k link supporting 50 virtual circuits

x25 htc 50

!

interface serial1

description T1 line supporting 500 virtual circuits

x25 htc 500

!

x25 hunt-group hg-vc vc-count

interface serial0

interface serial1

!

Hunt Group Configuration Example

The following example shows the creation of hunt group "HG1" with serial interfaces 1 and 2 and two specific XOT target IP addresses (172.17.125.54 and 172.17.125.34). Hunt group "HG1" is configured to use rotary distribution method. The example also shows the creation of hunt group "HG2" with serial interfaces 0 and 3. Hunt group "HG2" will use vc-count distribution method.

Related Commands

x25 idle

To define the period of inactivity after which the router can clear a switched virtual circuit (SVC), use the x25 idle interface configuration command.

x25 idle minutes

Syntax Description

minutes

Idle period in minutes.

Defaults

0 (the SVC is kept open indefinitely)

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

Calls originated and terminated by the router are cleared; packet assembler/disassembler (PAD) and switched virtual circuits are not affected. To clear one or all virtual circuits at once, use the clear x25 privileged EXEC command.

Examples

The following example sets a 5-minute wait period before an idle circuit is cleared:

interface serial 2

x25 idle 5

Related Commands

x25 ip-precedence

To enable the Cisco IOS software to use the IP precedence value when it opens a new virtual circuit (VC), use the x25 ip-precedence interface configuration command. To cause the Cisco IOS software to ignore the precedence value when opening VCs, use the no form of this command.

x25 ip-precedence

no x25 ip-precedence

Syntax Description

This command has no arguments or keywords.

Defaults

The router opens one VC for all types of service.

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This feature is useful only for Defense Data Network (DDN) or Blacker Front End (BFE) encapsulations because only these methods have an IP precedence facility defined to allow the source and destination devices to both use the VC for traffic of the given IP priority.

Verify that your host does not send nonstandard data in the IP type of service (TOS) field because it can cause multiple wasteful virtual circuits to be created.

Four VCs may be opened based on IP precedence to encapsulate routine, priority, immediate, and all higher precedences.

The x25 map nvc limit or the default x25 nvc limit still applies.

Examples

The following example allows new IP encapsulation VCs based on the IP precedence:

interface serial 3

x25 ip-precedence

x25 ips

To set the interface default maximum input packet size to match that of the network, use the x25 ips interface configuration command.

x25 ips bytes

Syntax Description

bytes

Byte count. It can be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

Defaults

128 bytes

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

X.25 network connections have a default maximum input packet size set by the network administrator. Larger packet sizes require less overhead processing. To send a packet larger than the X.25 packet size over an X.25 virtual circuit, the Cisco IOS software must break the packet into two or more X.25 packets with the more data bit (M-bit) set. The receiving device collects all packets with the M-bit set and reassembles the original packet.

Note Set the x25 ips and x25 ops commands to the same value unless your network supports asymmetric input and output packet sizes.

Related Commands

Sets the interface default maximum output packet size to match that of the network.

x25 lic

To set the lowest incoming-only virtual circuit (VC) number, use the x25 lic interface configuration command.

x25 lic circuit-number

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no incoming-only VC range.

Defaults

0

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command is applicable only if you have the X.25 switch configured for an incoming-only VC range. Incoming is from the perspective of the X.25 DTE device. If you do not want any outgoing calls on your DTE device, disable the two-way range (set the values of x25 ltc and x25 htc to 0).

The following example sets a valid incoming-only VC range of 1 to 5, and sets the lowest two-way VC number:

interface serial 0

x25 lic 1

x25 hic 5

x25 ltc 6

Related Commands

x25 linkrestart

To force X.25 Level 3 (packet level) to restart when Level 2 (Link Access Procedure, Balanced [LAPB], the link level) resets, use the x25 linkrestart interface configuration command. To disable this function, use the no form of this command.

x25 linkrestart

no x25 linkrestart

Syntax Description

This command has no arguments or keywords.

Defaults

Forcing packet-level restarts is the default and is necessary for networks that expect this behavior.

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Examples

The following example disables the link-level restart:

interface serial 3

no x25 linkrestart

x25 loc

To set the lowest outgoing-only virtual circuit (VC) number, use the x25 loc interface configuration command.

x25 loc circuit-number

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no outgoing-only VC range.

Defaults

0

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command is applicable only if you have the X.25 switch configured for an outgoing-only VC range. Outgoing is from the perspective of the X.25 DTE device. If you do not want any incoming calls from your DTE device, configure the values of x25 loc and x25 hoc and set the values of x25 ltc and x25 htc to 0.

Examples

The following example sets a valid outgoing-only virtual circuit range of 2000 to 2005:

Related Commands

x25 ltc

To set the lowest two-way virtual circuit (VC) number, use the x25 ltc interface configuration command.

x25 ltc circuit-number

Syntax Description

circuit-number

VC number from 1 to 4095, or 0 if there is no two-way VC range.

Defaults

1

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

This command is applicable if you have the X.25 switch configured for a two-way virtual circuit range. Any two-way virtual circuit range must come after (that is, be numerically larger than) any incoming-only range, and must come before any outgoing-only range.

Examples

The following example sets a valid two-way virtual circuit range of 5 to 25:

interface serial 0

x25 ltc 5

x25 htc 25

Related Commands

x25 map

To set up the LAN protocols-to-remote host mapping, use the x25 map interface configuration command. To retract a prior mapping, use the no form of this command with the appropriate network protocols and X.121 address argument.

Syntax Description

Protocol type, entered by keyword. Supported protocols are entered by keyword, as listed in Table 56. As many as nine protocol and address pairs can be specified in one command line.

address

Protocol address.

x121-address

X.121 address of the remote host.

option

(Optional) Additional functionality that can be specified for originated calls. Can be any of the options listed in Table 57.

Defaults

No LAN protocol-to-remote host mapping is set up.

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

Because no defined protocol can dynamically determine LAN protocol-to-remote host mappings, you must enter all the information for each host with which the router may exchange X.25 encapsulation traffic.

Two methods are available to encapsulate traffic: Cisco's long-available encapsulation method and the Internet Engineering Task Force (IETF) standard method (defined in RFC 1356); the latter allows hosts to exchange several protocols over a single virtual circuit. Cisco's encapsulation method is the default (for backward compatibility) unless the interface configuration command specifies the ietf keyword.

When you configure multiprotocol maps, you can specify a maximum of nine protocol and address pairs in an x25 map command. However, you can specify a protocol only once. For example, you can specify the IP protocol and an IP address, but you cannot specify another IP address. If the compressedtcp and ip keywords are both specified, the same IP address must be used.

Bridging is supported only if you are using Cisco's traditional encapsulation method. For correct operation, bridging maps must specify the broadcast option.

Since most datagram routing protocols rely on broadcasts or multicasts to send routing information to their neighbors, the broadcast keyword is needed to run such routing protocols over X.25.

Encapsulation maps might also specify that traffic between the two hosts should be compressed, thus increasing the effective bandwidth between them at the expense of memory and computation time. Because each compression virtual circuit requires memory and computation resources, compression must be used with care and monitored to maintain acceptable resource usage and overall performance.

Open Shortest Path First (OSPF) Protocol treats a nonbroadcast, multiaccess network such as X.25 in much the same way as it treats a broadcast network by requiring the selection of a designated router. In previous releases, this required manual assignment in the OSPF configuration using the neighbor router configuration command. When the x25 map command is included in the configuration with the broadcast, and the ip ospf network command (with thebroadcast keyword) is configured, there is no need to configure any neighbors manually. OSPF will now run over the X.25 network as a broadcast network. (Refer to the ip ospf network interface configuration command for more detail.)

Note The OSPF broadcast mechanism assumes that IP class D addresses are never used for regular traffic over X.25.

You can modify the options of an x25 map command by restating the complete set of protocols and addresses specified for the map, followed by the desired options. To delete a map command, you must also specify the complete set of protocols and addresses; the options can be omitted when deleting a map.

Once defined, a map's protocols and addresses cannot be changed. This requirement exists because the Cisco IOS software cannot determine whether you want to add to, delete from, or modify an existing map's protocol and address specification, or simply mistyped the command. To change a map's protocol and address specification, you must delete it and create a new map.

A given protocol-address pair cannot be used in more than one map on the same interface.

Causes the Cisco IOS software to accept incoming reverse-charged calls. If this option is not present, the Cisco IOS software clears reverse-charged calls unless the interface accepts all reverse-charged calls.

broadcast

Causes the Cisco IOS software to direct any broadcasts sent through this interface to the specified X.121 address. This option also simplifies the configuration of OSPF; see "Usage Guidelines" for more detail.

cuggroup-number

Specifies a closed user group (CUG) number (from 1 to 9999) for the mapping in an outgoing call.

compress

Specifies that X.25 payload compression be used for mapping the traffic to this host. Each virtual circuit established for compressed traffic uses a significant amount of memory (for a table of learned data patterns) and for computation (for compression and decompression of all data). Cisco recommends that compression be used with careful consideration of its impact on overall performance.

idleminutes

Specifies an idle timeout for calls other than the interface default; 0 minutes disables the idle timeout.

method {cisco | ietf | snap | multi}

Specifies the encapsulation method. The choices are as follows:

•cisco—Cisco's proprietary encapsulation; not available if more than one protocol is to be carried.

•ietf—Default RFC 1356 operation: protocol identification of single-protocol virtual circuits and protocol identification within multiprotocol virtual circuits use the standard encoding, which is compatible with RFC 877. Multiprotocol virtual circuits are used only if needed.

•snap—RFC 1356 operation where IP is identified with SNAP rather than the standard IETF method (the standard method is compatible with RFC 877).

•multi—Forces a map that specifies a single protocol to set up a multiprotocol virtual circuit when a call is originated; also forces a single-protocol PVC to use multiprotocol data identification methods for all datagrams sent and received.

no-incoming

Use the map only to originate calls.

no-outgoing

Do not originate calls when using the map.

nudatastring

Specifies the network user identification in a format determined by the network administrator (as allowed by the standards). This option is provided for connecting to non-Cisco equipment that requires an NUID facility. The string should not exceed 130 characters and must be enclosed in quotation marks (" ") if there are any spaces present. This option only works if the router is configured as an X.25 DTE.

nuid username password

Specifies that a network user ID (NUID) facility be sent in the outgoing call with the specified TACACS username and password (in a format defined by Cisco). This option should be used only when connecting to another Cisco router. The combined length of the username and password should not exceed 127 characters. This option only works if the router is configured as an X.25 data terminal equipment (DTE).

nvccount

Sets the maximum number of virtual circuits for this map or host. The default count is the x25 nvc setting of the interface. A maximum number of eight virtual circuits can be configured for each map. Compressed TCP may use only 1 virtual circuit.

packetsize in-size out-size

Proposes maximum input packet size (in-size) and maximum output packet size (out-size) for an outgoing call. Both values typically are the same and must be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

passive

Specifies that the X.25 interface should send compressed outgoing TCP datagrams only if they were already compressed when they were received. This option is available only for compressed TCP maps.

reverse

Specifies reverse charging for outgoing calls.

roa name

Specifies the name defined by the x25 roa command for a list of transit Recognized Operating Agencies (ROAs, formerly called Recognized Private Operating Agencies, or RPOAs) to use in outgoing Call Request packets.

throughput in out

Sets the requested throughput class values for input (in) and output (out) throughput across the network for an outgoing call. Values for in and out are in bits per second (bps) and range from 75 to 48000 bps.

transit-delaymilliseconds

Specifies the transit delay value in milliseconds (0 to 65534) for an outgoing call, for networks that support transit delay.

windowsize in-size out-size

Proposes the packet count for input window (in-size) and output window (out-size) for an outgoing call. Both values typically are the same, must be in the range 1 to 127, and must be less than the value set by the x25 modulo command.

Examples

The following example maps IP address 172.20.2.5 to X.121 address 000000010300. The broadcast keyword directs any broadcasts sent through this interface to the specified X.121 address.

interface serial 0

x25 map ip 171.20.2.5 000000010300 broadcast

The following example specifies an ROA name to be used for originating connections:

x25 roa green_list 23 35 36

interface serial 0

x25 map ip 172.20.170.26 10 roa green_list

The following example specifies an NUID facility to send on calls originated for the address map:

interface serial 0

x25 map ip 172.20.174.32 2 nudata "Network User ID 35"

Strings can be quoted, but quotation marks are not required unless embedded blanks are present.

Related Commands

Command

Description

ip ospf network

Configures the OSPF network type to a type other than the default for a given medium.

x25 map bridge

To configure an Internet-to-X.121 address mapping for bridging of packets in X.25 frames, use the x25 map bridge interface configuration command. Use the no form of this command to disable the Internet-to-X.121 address mapping.

x25 map bridge x121-addressbroadcast[option]

Syntax Description

x121-address

The X.121 address.

broadcast

Required keyword for bridging over X.25.

option

(Optional) Services that can be added to this map (same options as the x25 map command). See Table 6 for more details.

Defaults

No bridging over X.25 is configured.

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

The X.25 bridging software uses the same spanning-tree algorithm as the other bridging functions, but allows packets to be encapsulated in X.25 frames and transmitted across X.25 media. This command specifies IP-to-X.121 address mapping and maintains a table of both the Ethernet and X.121 addresses.

Causes the Cisco IOS software to accept incoming reverse-charged calls. If this option is not present, the Cisco IOS software clears reverse-charged calls unless the interface accepts all reverse-charged calls.

broadcast

Causes the Cisco IOS software to direct any broadcasts sent through this interface to the specified X.121 address. This option also simplifies the configuration of Open Shortest Path First (OSPF) Protocol; see "Usage Guidelines" for more detail.

compress

Specifies that X.25 payload compression be used for mapping the traffic to this host. Each virtual circuit established for compressed traffic uses a significant amount of memory (for a table of learned data patterns) and for computation (for compression and decompression of all data). Cisco recommends that compression be used with careful consideration of its impact on overall performance.

cuggroup-number

Specifies a closed user group (CUG) number (from 1 to 9999) for the mapping in an outgoing call.

idleminutes

Specifies an idle timeout for calls other than the interface default; 0 minutes disables the idle timeout.

method {cisco | ietf | snap | multi}

Specifies the encapsulation method. The choices are as follows:

•cisco—Cisco's proprietary encapsulation; not available if more than one protocol is to be carried.

•ietf—Default RFC 1356 operation: protocol identification of single-protocol virtual circuits and protocol identification within multiprotocol virtual circuits use the standard encoding, which is compatible with RFC 877. Multiprotocol virtual circuits are used only if needed.

•snap—RFC 1356 operation where IP is identified with SNAP rather than the standard Internet Engineering Task Force (IETF) method (the standard method is compatible with RFC 877).

•multi—Forces a map that specifies a single protocol to set up a multiprotocol virtual circuit when a call is originated; also forces a single-protocol permanent virtual circuit (PVC) to use multiprotocol data identification methods for all datagrams sent and received.

no-incoming

Uses the map only to originate calls.

no-outgoing

Does not originate calls when using the map.

nudatastring

Specifies the network user identification in a format determined by the network administrator (as allowed by the standards). This option is provided for connecting to non-Cisco equipment that requires an NUID facility. The string should not exceed 130 characters and must be enclosed in quotation marks (" ") if there are any spaces present. This option only works if the router is configured as an X.25 DTE device.

nuid username password

Specifies that a network user ID (NUID) facility be sent in the outgoing call with the specified Terminal Access Controller Access Control System (TACACS) username and password (in a format defined by Cisco). This option should be used only when connecting to another Cisco router. The combined length of the username and password should not exceed 127 characters. This option only works if the router is configured as an X.25 DTE.

nvccount

Sets the maximum number of virtual circuits for this map or host. The default count is the x25 nvc setting of the interface. A maximum number of eight virtual circuits can be configured for each map. Compressed TCP may use only 1 virtual circuit.

packetsize in-size out-size

Proposes maximum input packet size (in-size) and maximum output packet size (out-size) for an outgoing call. Both values typically are the same and must be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

passive

Specifies that the X.25 interface should send compressed outgoing TCP datagrams only if they were already compressed when they were received. This option is available only for compressed TCP maps.

reverse

Specifies reverse charging for outgoing calls.

roa name

Specifies the name defined by the x25 roa command for a list of transit Recognized Operating Agencies (ROAs, formerly called Recognized Private Operating Agencies, or RPOAs) to use in outgoing Call Request packets.

throughput in out

Sets the requested throughput class values for input (in) and output (out) throughput across the network for an outgoing call. Values for in and out are in bits per second (bps) and range from 75 to 48000 bps.

transit-delaymilliseconds

Specifies the transit delay value in milliseconds (0 to 65534) for an outgoing call, for networks that support transit delay.

windowsize in-size out-size

Proposes the packet count for input window (in-size) and output window (out-size) for an outgoing call. Both values typically are the same, must be in the range 1 to 127, and must be less than the value set by the x25 modulo command.

Examples

The following example configures transparent bridging over X.25 between two Cisco routers using a maximum of six virtual circuits:

Related Commands

x25 map cmns

The x25 map cmns command is replaced by the enhanced x25 route command. See the description of the x25 route command in this chapter for more information.

x25 map compressedtcp

To map compressed TCP traffic to an X.121 address, use the x25 map compressedtcp interface configuration command. To delete a TCP/IP header compression map for the link, use the no form of this command.

Syntax Description

ip-address

IP address.

protocol

(Optional) Protocol type, entered by keyword. Supported protocols are entered by keyword, as listed in Table 56 earlier in this chapter. As many as nine protocol and address pairs can be specified in one command line.

address

(Optional) Protocol address.

x121-address

X.121 address.

option

(Optional) The same options as those for the x25 map command; see Table 57 earlier in this chapter.

Defaults

No mapping is configured.

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

Cisco supports RFC 1144 TCP/IP header compression (THC) on serial lines using HDLC and X.25 encapsulation. THC encapsulation is only slightly different from other encapsulation traffic, but these differences are worth noting. The implementation of compressed TCP over X.25 uses one virtual circuit to pass the compressed packets. Any IP traffic (including standard TCP) is separate from TCH traffic; it is carried over separate IP encapsulation virtual circuits or identified separately in a multiprotocol virtual circuit.

Note If you specify both ip and compressedtcp in the same x25 map compressedtcp command, they must both specify the same IP address.

The nvc map option cannot be used for TCP/IP header compression, because only one virtual circuit can carry compressed TCP/IP header traffic to a given host.

Examples

The following example establishes a map for TCP/IP header compression on serial interface 4:

Syntax Description

(Optional) Services that can be added to this map—the same options as the x25 map command; see Table 57 earlier in this chapter.

Defaults

No specific options are used for PAD access.

Command Modes

Interface configuration

Command History

Release

Modification

10.2

This command was introduced.

Usage Guidelines

Use a PAD map to configure optional X.25 facility use for PAD access. When used with the x25 pad-access interface configuration command, the x25 map pad command restricts incoming PAD access to those statically mapped hosts.

Examples

The following example configures an X.25 interface to restrict incoming PAD access to the single mapped host. This example requires that both incoming and outgoing PAD access use the network user identification (NUID) user authentication.

Related Commands

x25 modulo

To set the window modulus, use the x25 modulo interface configuration command.

x25 modulo modulus

Syntax Description

modulus

Either 8 or 128. The value of the modulo parameter must agree with that of the device on the other end of the X.25 link.

Defaults

8

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

X.25 supports flow control with a sliding window sequence count. The window counter restarts at zero upon reaching the upper limit, which is called the window modulus. Modulo 128 operation is also referred to as extended packet sequence numbering, which allows larger packet windows.

Changes the default outgoing window size to match that of the network.

x25 nvc

To specify the maximum number of virtual circuits (VCs) that a protocol can have open simultaneously to one host, use the x25 nvc interface configuration command. To increase throughput across networks, you can establish up to eight virtual circuits to a host and protocol.

x25 nvc count

Syntax Description

count

Circuit count from 1 to 8. A maximum of eight virtual circuits can be configured for each protocol-host pair. Protocols that do not tolerate out-of-sequence delivery, such as encapsulated TCP/IP header compression, will use only one virtual circuit despite this value. Permitting more than one VC may help throughput on slow networks.

Defaults

1

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

When the windows and output queues of all existing connections to a host are full, a new virtual circuit will be opened to the designated circuit count. If a new connection cannot be opened, the data is dropped.

Note The count value specified for thex25 nvc command affects the default value for the number of VCs. It does not affect the nvc option for any x25 map commands that are configured.

Examples

The following example sets the default maximum number of VCs that each map can have open simultaneously to 4:

interface serial 0

x25 nvc 4

x25 ops

To set the interface default maximum output packet size to match that of the network, use the x25 ops interface configuration command.

x25 ops bytes

Syntax Description

bytes

Byte count that is one of the following: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

Defaults

128 bytes

Command Modes

Interface configuration

X.25 profile configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

X.25 networks use maximum output packet sizes set by the network administrator. Larger packet sizes are better because smaller packets require more overhead processing. To send a packet larger than the X.25 packet size over an X.25 virtual circuit, the Cisco IOS software must break the packet into two or more X.25 packets with the more data bit (M-bit) set. The receiving device collects all packets with the M-bit set and reassembles the original packet.

Note Set the x25 ips and x25 ops commands to the same value unless your network supports asymmetry between input and output packets.

Examples

The following example sets the default maximum packet sizes to 512:

interface serial 1

x25 ips 512

x25 ops 512

Related Commands

Sets the interface default maximum input packet size to match that of the network.

x25 pad-access

To cause the packet assembler/disassembler (PAD) software to accept PAD connections only from statically mapped X.25 hosts, use the x25 pad-access interface configuration command. To disable checking maps on PAD connections, use the no form of this command.

x25 pad-access

no x25 pad-access

Syntax Description

This command has no arguments or keywords.

Defaults

Accept PAD connections from any host.

Command Modes

Interface configuration

Command History

Release

Modification

10.2

This command was introduced.

Usage Guidelines

By default, all PAD connection attempts are processed for session creation or protocol translation, subject to the configuration of those functions. If you use the x25 pad-access command, PAD connections are processed only for incoming calls with a source address that matches a statically mapped address configured with the x25 map pad interface configuration command. PAD connections are refused for any incoming calls with a source address that has not been statically mapped.

Examples

The following example restricts incoming PAD access on the interface to attempts from the host with the X.121 address 000000010300:

Related Commands

x25 pvc (encapsulation)

To establish an encapsulation permanent virtual circuit (PVC), use the encapsulating version of the x25 pvc interface configuration command. To delete the PVC, use the no form of this command with the appropriate channel number.

Syntax Description

Virtual-circuit channel number, which must be less than the virtual circuits assigned to the switched virtual circuits (SVCs).

protocol

Protocol type, entered by keyword. Supported protocols are listed in Table 61. As many as nine protocol and address pairs can be specified in one command line.

address

Protocol address of the host at the other end of the PVC.

x121-address

X.121 address.

option

(Optional) Provides additional functionality or allows X.25 parameters to be specified for the PVC.Can be any of the options listed in Table 62.

Defaults

The PVC window and maximum packet sizes default to the interface default values.

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

PVCs are not supported for ISO Connection-Mode Network Service (CMNS).

You no longer need to specify a datagram protocol-to-address mapping before you can set up a PVC; a map is implied from the PVC configuration. Configurations generated by the router will no longer specify a map for encapsulating PVCs.

When configuring a PVC to carry CLNS traffic, use the X.121 address as the subnetwork point of attachment (SNPA) to associate the PVC with a CLNS neighbor configuration. When configuring a PVC to carry transparent bridge traffic, the X.121 address is required to identify the remote host to the bridging function. Other encapsulation PVCs do not require an X.121 address.

Causes the Cisco IOS software to direct any broadcasts sent through this interface to this PVC. This option also simplifies the configuration of OSPF.

method {cisco | ietf | snap | multi}

Specifies the encapsulation method. The choices are as follows:

•cisco—Single protocol encapsulation; not available if more than one protocol is carried.

•ietf—Default RFC 1356 operation; single-protocol encapsulation unless more than one protocol is carried, and protocol identification when more than one protocol is carried.

•snap—RFC 1356 operation where IP is identified when more than one protocol is carried using the SNAP encoding.

•multi—Multiprotocol encapsulation used on the PVC.

packetsize in-size out-size

Maximum input packet size (in-size) and output packet size (out-size) for the PVC. Both values are typically the same and must be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

passive

Specifies that transmitted TCP datagrams will be compressed only if they were received compressed. This option is available only for PVCs carrying compressed TCP/IP header traffic.

windowsizein-size out-size

Packet count for input window (in-size) and output window (out-size) for the PVC. Both values are typically the same, must be in the range 1 to 127, and must be less than the value set for the x25 modulo command.

Examples

The following example establishes a PVC on channel 2 to encapsulate VINES and IP with the far host:

Related Commands

x25 pvc (switched)

To configure a switched permanent virtual circuit (PVC) for a given interface, use the switched version of the x25 pvc interface configuration command.

x25 pvcnumber1 interface typenumber pvc number2 [option]

Syntax Description

number1

PVC number that will be used on the local interface (as defined by the primary interface command).

interface

Required keyword to specify an interface.

type

Remote interface type.

number

Remote interface number.

pvc

Required keyword to specify a switched PVC.

number2

PVC number that will be used on the remote interface.

option

(Optional) Adds certain features to the mapping specified; can be either option listed in Table 63.

Defaults

The PVC window and maximum packet sizes default to the interface default values.

Command Modes

Interface configuration

Command History

Release

Modification

10.0

This command was introduced.

Usage Guidelines

You can configure X.25 PVCs in the X.25 switching software. As a result, data terminal equipment (DTE) devices that require permanent circuits can be connected to the router acting as an X.25 switch and have a properly functioning connection. X.25 resets will be sent to indicate when the circuit comes up or goes down.

PVC circuit numbers must come before (that is, be numerically smaller than) the circuit numbers allocated to any SVC range.

Maximum input packet size (in-size) and output packet size (out-size) for the PVC. Both values must be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

windowsizein-size out-size

Packet count for input window (in-size) and output window (out-size) for the PVC. Both values should be the same, must be in the range 1 to 127, and must not be greater than the value set for the x25 modulo command.

Examples

The following example configures a PVC connected between two serial interfaces on the same router. In this type of interconnection configuration, the alternate interface must be specified along with the PVC number on that interface. To make a working PVC connection, two commands must be specified, each pointing to the other, as this example illustrates.

interface serial 0

encapsulation x25

x25 ltc 5

x25 pvc 1 interface serial 1 pvc 1

interface serial 1

encapsulation x25

x25 ltc 5

x25 pvc 1 interface serial 0 pvc 1

x25 pvc (switched PVC to SVC)

To configure a switched permanent virtual circuit (PVC) to a switched virtual circuit (SVC) for a given interface, use the switched PVC to SVC version of the x25 pvc interface configuration command.

(Optional) Adds certain features to the mapping specified. It can be any of the options listed in Table 64.

call-control-options

(Optional) Adds certain features to the mapping specified. It can be any of the options listed in Table 65.

Defaults

This command has no default values.

Command Modes

Interface configuration

Command History

Release

Modification

11.2 F

This command was introduced.

Usage Guidelines

The PVC window and maximum packet sizes default to the interface default values. The default idle time comes from the interface on which the x25 pvc command is configured, not the interface on which the call is sent/received.

PVC circuit numbers must come before (that is, be numerically smaller than) the circuit numbers allocated to any SVC range.

On an outgoing call, the packet size facilities and window size facilities will be included. The call will be cleared if the call accepted packet specifies different values.

On an incoming call, requested values that do not match the configured values will be refused.

Table 64 lists the flow control options supported by X.25 during PVC to SVC switching.

Table 64 x25 pvc Flow Control Options

Option

Description

packetsize in-size out-size

Maximum input packet size (in-size) and output packet size (out-size) for both the PVC and SVC. Values may differ but must be one of the following: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

windowsize in-size out-size

Packet count for input window (in-size) and output window (out-size) for both the PVC and SVC. Both values may differ but must be in the range 1 to 127 and must be less than the value set for the x25 modulo command.

Table 65 lists the call control options supported by X.25 during PVC to SVC switching.

Table 65 x25 pvc Call Control Options

Option

Description

accept-reverse

Causes the Cisco IOS software to accept incoming reverse-charged calls. If this option is not present, the Cisco IOS software clears reverse-charged calls unless the interface accepts all reverse-charged calls.

idleminutes

Idle time-out for the SVC. This option will override the interface's x25 idle commandvalue only for this circuit.

no-incoming

Establishes a switched virtual circuit to the specified X.121 address when data is received from the permanent virtual circuit, but does not accept calls from this X.121 address.

no-outgoing

Accepts an incoming call from the specified X.121 address, but does not attempt to place a call when data is received from the permanent virtual circuit. If data is received from the permanent virtual circuit while no call is connected, the PVC will be reset.

Examples

The following example configures PVC to SVC switching between two serial interfaces:

Any call with a destination address beginning with 20 will be routed to serial interface 0. Any call with a destination address beginning with 10 will be routed to serial interface 2. (Note that incoming calls will not be routed back to the same interface from which they arrived.)

Traffic received on PVC 5 on serial interface 0 will cause a call to be placed from address 201700 to the X.121 address 101601. The routing table will then forward the call to serial interface 2. If no data is sent or received on the circuit for two minutes, the call will be cleared, as defined by the x25 idle command. All incoming calls from 101601 to 201700 will be refused, as defined by the no-incoming attribute.

The second x25 pvc command configures the circuit to allow incoming calls from 101602 to 201700 to be connected to PVC 6 on serial interface 1. Because idle is set to 0, the call will remain connected until cleared by the remote host or an X.25 restart. Because outgoing calls are not permitted for this connection, if traffic is received on PVC 6 on serial interface 0 before the call is established, the traffic will be discarded and the PVC will be reset.

The last x25 pvc command configures the circuit to accept an incoming call from 101603 to 201700 and connects the call to PVC 7 on serial interface 0. If no data is sent or received on the circuit for two minutes, the call will be cleared. If traffic is received on PVC 7 on serial interface 0 before the call is established, a call will be placed to 101503 to 201700.

x25 pvc (XOT)

To connect two permanent virtual circuits (PVCs) across a TCP/IP LAN, use the X.25-over-TCP (XOT) service form of the x25 pvc interface configuration command.

Serial interface specification that accepts either a number or a string in model 7000 format (number/number) to denote the serial interface.

pvc

Indicates a PVC.

number2

Remote PVC number on the target interface.

option

(Optional) Adds certain features for the connection; can be one or more of the options listed in Table 66.

Defaults

The PVC window and packet sizes default to the interface default values.

The default for the xot-keepalive-period option is 60 seconds.

The default for the xot-keepalive-tries option is 4 tries.

Command Modes

Interface configuration

Command History

Release

Modification

10.3

This command was introduced.

Usage Guidelines

Use the PVC tunnel commands to tell the Cisco IOS software what the far end of the PVC is connected to. The incoming and outgoing packet sizes and window sizes must match the remote PVC outgoing and incoming sizes.

It is recommended that the xot-source option be used on the remote host so that a consistent IP address is used for the connection.

Maximum input packet size (in-size) and output packet size (out-size) for the PVC. Both values must be one of the following values: 16, 32, 64, 128, 256, 512, 1024, 2048, or 4096.

windowsizein-size out-size

Packet count for input window (in-size) and output window (out-size) for the PVC. Both values should be the same, must be in the range 1 to 127, and must not be greater than or equal to the value set for the x25 modulo command.

xot-keepalive-periodseconds

Number of seconds between keepalives for XOT connections. The default is 60 seconds.

xot-keepalive-triescount

Number of times TCP keepalives should be sent before dropping the connection. The default value is 4 times.

xot-promiscuous

Indicates that the remote IP address should be ignored when matching an incoming XOT connection with the XOT PVC parameters.

xot-sourceinterface

Specifies an interface whose IP address should be used as the local IP address of the TCP connection.

Each XOT connection relies on a TCP session to carry traffic. To ensure that these TCP sessions remain connected in the absence of XOT traffic, use the service tcp-keepalives-in and service tcp-keepalives-out global configuration commands. If TCP keepalives are not enabled, the XOT PVCs might encounter problems if one end of the connection is reloaded. When the reloaded host attempts to establish a new connection, the other host refuses the new connection because it has not been informed that the old session is no longer active. Recovery from this state requires the other host to be informed that its TCP session is no longer viable so that it attempts to reconnect the PVC.